The invention relates to roof ventilators for closed vehicles such as buses, trailers, trucks, and railroad cars, and particularly to an improved closure or lid by which the ventilator opening in the roof of such a vehicle may also serve as an escape hatch for occupants in the vehicle in the event of an accident or other emergency rendering the normal means of egress unusable. More specifically, the invention is an improvement in the escape hatch operating mechanism as shown in my earlier U.S. Pat. No. 4,021,073.
In its more specific aspects, the invention provides a lid or hatch which in normal operation either closes the roof opening or is raised to a variety of partially elevated or open positions when ventilation of the vehicle so requires, and which lid can be manually released and forced upwardly to swing fully open in the event of an emergency requiring use of the roof opening as an escape hatch.
Roof ventilators employing a lid or hatch which can be tilted upwardly are well known in the prior art, including such a lid that can be so tilted in either of two directions for directing air into or exhausting air out of the vehicle. U.S. Pat. Nos. 2,173,890 to Tuttle and 2,372,164 to Woodhams, for example, show vehicle roof ventilator panels tiltable upwardly in one direction, and U.S. Pat. No. 2,159,516 to Ball shows one tiltable alternatively for exhausting air from the vehicle interior or by suction or by the deflection of air into the vehicle. Also, U.S. Pat. No. 2,517,303 to Green discloses a roof ventilator in which the closure lid may be raised vertically, rather than tilted angularly of the roof opening. Other than my own earlier patent, the closest art to the invention, of which applicant is aware, is probably U.S. Pat. No. 3,676,954 Rapport et al showing a lid for a vehicle roof vent opening which is tiltable upwardly to a venting position by means of a worm gear and wheel drive mechanism and which has means for unlatching the housing of the worm mechanism to allow the lid to be swung to a fully open position.